A cross between the definitive puzzle game Tetris and the niche arcade classic Rampart, Fortress has plenty of substance, but doesn't take advantage of the Game Boy Advance's visual and aural capabilities. The game challenges players to construct towers from Tetris-like pieces, while simultaneously trying to destroy their opponent's structure and defend their own. Players use a variety of weapons and units to achieve their aims. Twerps are the grunts of the game and come in two varieties: offensive and defensive. Offensive twerps attack your opponent, while defensive twerps help repair your structure. Wizards will summon monsters that can inflict massive damage to your enemy. Weaponry is dependent on which level you are playing--prehistoric, medieval, pirate or space. Prehistoric weapons are primitive (rocks and slingshots), while space weapons are futuristic (plasma cannons). There are three gameplay modes: battle, blitz, and tournament. Unfortunately, the modes are very similar and don't greatly affect the way you play the game. Single-player games are great for quick doses of addictive action, but two-player games through a link cable can be outstanding. The caveat is that the game's nuances might be difficult for some users to pick up. The manual does a fine job of defining everything that's in the game, but a poor job explaining how to tie it all together. An in-game tutorial would have helped immensely. While the graphics and sound won't dazzle anyone, this game is both addictive and deep--a winning combination for a puzzle game. --Raymond M Padilla